When implementing an Ethernet network, network managers and engineers can deploy NICs from a variety of vendors on the same network. Because of the stable IEEE 802.3 standard that specifies the protocols and electrical characteristics that manufacturers must follow for Ethernet, these products all speak exactly the same language. This uniformity enables you to select products that meet your requirements at the lowest cost from a variety of manufacturers.
With wireless LANs, you can't assume interoperability in all situations. There are still pre-802.11 (proprietary) wireless LANs, both frequency-hopping and direct sequence 802.11 versions, and vendor-specific enhancements to 802.11-compliant products that make interoperability questionable. To ensure interoperability with wireless LANs, it's best to implement radio cards and access points from the same vendor, if possible. You can successfully implement multivendor wireless LANs, but wireless LAN features are reduced to the lowest common denominator and may not make use of valuable vendor-specific enhancements of their wireless LAN products.